{"id":800093,"date":"2019-10-04T17:57:18","date_gmt":"2019-10-04T23:57:18","guid":{"rendered":"https:\/\/www.summitdaily.com\/?p=372527"},"modified":"2019-10-04T17:57:18","modified_gmt":"2019-10-04T23:57:18","slug":"experts-detail-march-2019-avalanche-cycle-at-colorado-snow-and-avalanche-workshop-in-breckenridge","status":"publish","type":"post","link":"https:\/\/alwaysmountaintime.com\/ksmt\/local-news\/experts-detail-march-2019-avalanche-cycle-at-colorado-snow-and-avalanche-workshop-in-breckenridge\/","title":{"rendered":"Experts detail March 2019 avalanche cycle at Colorado Snow and Avalanche Workshop in Breckenridge"},"content":{"rendered":"
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CDOT crews work to remove the snow debris from a controlled avalanche that spilled onto Interstate 70 March 5, near Loveland Pass.<\/strong>
Summit Daily file<\/em><\/figcaption><\/div>\n<\/figure>\n

BRECKENRIDGE \u2013 At Friday\u2019s 18th annual Colorado Snow and Avalanche Workshop in Breckenridge, Art Mears shared a story that spoke to the core of this past March\u2019s historic avalanche cycle.<\/p>\n

Mears, an experienced avalanche consultant based in Gunnison, told of how his wife once looked up at an avalanche slide path near Avery Peak in Crested Butte. She turned to her husband and asked him why couldn\u2019t an avalanche in the path they were looking at run all the way to where their car was currently located on the road.<\/p>\n

\u201c\u2018I don\u2019t think the conditions will ever be quite right for it to run that big,\u2019\u201d Mears remembers saying. \u201cThis year, it did exactly that.\u201d<\/p>\n

\u201cIt\u2019s certainly nothing like we\u2019ve ever seen,\u201d CAIC Deputy Director Brian Lazar said of the March 2019 avalanche cycle<\/a>. \u201cAnyone on staff was unanimous that we\u2019ve never seen anything like this in our careers.\u201d<\/p>\n

At Friday\u2019s Colorado Avalanche Information Center event at the Riverwalk Center in Breckenridge, Mears, Lazar and other speakers contextualized how and why this past March was an unprecedented year for snow and avalanches in Summit County and elsewhere in the state.<\/p>\n

Lazar began the day taking the audience through a chronology of what set last March up to be unprecedented. He explained how last October\u2019s early snowfall set the initial stage for the March cycle, as deposited snowpack layers weren\u2019t as weak as many other years. The subsequent snowfall until March, Lazar said, created a relatively deep and strong snowpack across the state, which was already more than four meters in the deepest areas.<\/p>\n

\u201cAnd in these really deep snowpack areas,\u201d Lazar said, \u201cthree to four meters on the ground, we weren\u2019t worried about them at all unless we got a massive loading event. \u201c\u2026we did realize the potential for unlikely, very large persistent slab avalanches to occur. But, again, we thought we\u2019d need something of epic proportions to get these things to break.\u201d<\/p>\n

March 2019 turned out to be epic. <\/p>\n

In the first week, between two-and-a-half and seven feet of snow dumped on most mountain areas. But, more importantly, Lazar explained, the snow water equivalent of the new snowfall manifested ideal conditions for big, powerful slides. Snow water equivalent measures the amount of water contained within the snowpack.<\/p>\n

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Come March 3, as slides began to run onto open highways \u2013 including two in Tenmile Canyon between Frisco and Copper Mountain<\/a> \u2013 Lazar said increases approaching 20% in snow water equivalent at heavy-snowfall locations helped CAIC experts like him to understand the uniqueness of the storm cycle. Considering the heavy, wet and copious nature of the maritime snowfall combining with the pre-existing strong snowpack that had yet to slide in many paths, avalanches on aspects of all kinds, slopes facing in all different directions, were possible.<\/p>\n

March 7 spoke directly to that. The day \u2014 known to many in Summit County as \u201cBlack Thursday\u201d as four backcountry zones went to extreme \u201cblack\u201d danger levels<\/a> \u2014 resulted in tremendously energetic slides on state Highway 91 just outside of Copper Mountain, rupturing gas lines<\/a>.<\/p>\n

\u201cThese are clear illustrations that this avalanche cycle was not aspect dependent,\u201d Lazar said. \u201cThis was running on all sides of the compass, on all elevations.\u201d<\/p>\n

Fast forward to March 9, where, on the other end of Summit County, transmission lines and towers in the Peru Creek basin near Montezuma were taken out. The nearby SNOTEL sensor measured a 38% increase in total snow water equivalent since the start of the month.<\/p>\n

Outside of Summit County, a handful of mega slides registered D5 on the United States Avalanche Rating Code, which measures destructive force. A D5, the highest rating, is defined as a slide so strong it can \u201cgouge\u201d the landscape. That\u2019s precisely what deposited into Conundrum Creek in the Maroon Bells-Snowmass Wilderness, a slide more than a mile wide and 3,200-feet long. It was one of several slides across the state in March that shocked experts by running up valleys, sheering rarely-touched landscape in the process.<\/p>\n

\u201cThis thing was a monster,\u201d Lazar said.<\/p>\n

How monstrous was last March? In terms of mere numbers, more than 1,000 avalanches were reported to the CAIC over two weeks, including 87 rated D4 or larger. None of these mega slides were triggered by humans, though.<\/p>\n

\u201cThese took inches and inches of water and feet and feet of snow or large (human-launched avalanche mitigation) explosives,\u201d Lazar said.<\/p>\n

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Lazar also said the cycle opened CAIC\u2019s eyes to classifying more slides as D5 in the future. He said many more slides in March actually fit two to three characteristics of a D5 slide. In terms of total slides, Lazar said CAIC estimates only 25% of March\u2019s total avalanches were reported.<\/p>\n

Pointing to the jaw-dropping Peak 1 slide, Lazar showed a photo indicating that the path had previously slid much the same way about 120 years ago, perhaps in the big snow year of 1898-99. Other historical photos show slides like this year\u2019s in Tenmile Canyon likely occurred during that same time frame, including images of early settlers clearing railways lines in the canyon in 1898-99.<\/p>\n

Mears\u2019 presentation subsequently spoke to the raw power of the avalanches. He said many of this year\u2019s avalanches were noteworthy because they were destructive in the total length of their paths. That variable speaks to just how much kinetic energy was loaded up and bonded together on slopes during March\u2019s cycle.<\/p>\n

\u201cTheoretically,\u201d Mears said, \u201cI knew a lot of these things could happen, but I never thought I\u2019d actually see it happen.\u201d<\/p>\n

via:: Summit Daily<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

CDOT crews work to remove the snow debris from a controlled avalanche that spilled onto Interstate 70 March 5, near Loveland Pass.Summit Daily file BRECKENRIDGE \u2013 At Friday\u2019s 18th annual Colorado Snow and Avalanche Workshop in Breckenridge, Art Mears shared a story that spoke to the core of this past March\u2019s historic avalanche cycle. Mears, […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[99],"tags":[],"class_list":{"0":"post-800093","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-local-news"},"acf":[],"publishpress_future_action":{"enabled":false,"date":"2026-06-24 22:26:32","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"distributor_meta":false,"distributor_terms":false,"distributor_media":false,"distributor_original_site_name":"KSMT The Mountain","distributor_original_site_url":"https:\/\/alwaysmountaintime.com\/ksmt","push-errors":false,"_links":{"self":[{"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/posts\/800093","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/comments?post=800093"}],"version-history":[{"count":0,"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/posts\/800093\/revisions"}],"wp:attachment":[{"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/media?parent=800093"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/categories?post=800093"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/alwaysmountaintime.com\/ksmt\/wp-json\/wp\/v2\/tags?post=800093"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}